Washington, July 22 : A new study by conservation biologists from the University of California, Berkeley, has indicated that allowing public access in wildlife reserves can scare off the native carnivore populations, findings which could have important implications for land management policies.
The study compared parks in the San Francisco Bay Area that allow only quiet recreation such as hiking or dog walking with nearby nature reserves that allow no public access.
Evidence of some native carnivore populations - coyote and bobcat - was more than five times lower in parks that allow public access than in neighboring reserves where humans don't tread, the researchers reported.
The dearth of these animals in the parks carries implications beyond just these species. Since the carnivores in the study are often the top predators in their areas, these animals also shape the rest of their surrounding ecosystems.
According to the researchers, the flight of large animals from heavily visited parks for more serene surroundings could, in turn, influence populations of small animals and plants.
"Carnivores are sensitive indicators of human disturbance," said Sarah Reed, postdoctoral scholar in UC Berkeley's Department of Environmental Science, Policy and Management and the study's lead author. "Their presence or absence can be a good, early clue to how the ecosystem is doing," she added.
To measure carnivore numbers, Reed studied the droppings of six native and non-native mammalian carnivores in 28 parks and preserves in northern California.
The parks in her study allow public access, but don't allow motorized vehicles or hunting and fishing. Most visitors to these parks hike or walk their dogs. The preserves in the study have limited or no public access.
Reed found more than five times as much coyote and bobcat scat in preserves with no public access than she did in the parks.
Coyotes and bobcats are both native carnivores.
She also found more scat from the native gray fox and the non-native red fox in unvisited areas, and more dog and cat droppings in visited parks.
Reed said that she had not expected these findings, as conservation biologists had assumed that activities such as hiking or horseback riding were relatively benign.
"I was surprised that the difference was so dramatic," she said.
According to Reed, the carnivores are leaving the parks for calmer neighboring areas.
Her study didn't address the reason for their flight, but she thinks it likely that the mere presence of humans disturbs the animals.
"The noise of humans traipsing and chatting through parks, our smell or just the sight of us could frighten animals away from their homes," she said.